Claritin D (loratadine and pseudoephedrine) and Claritin (loratadine) are antihistamines used to treat allergy symptoms. Claritin blocks the action of histamine, a substance in the body that initiates allergic symptoms like itching, sneezing, runny nose, and allergic skin rashes.

Benadryl (diphenhydramine) and Claritin (loratadine) are antihistamines used to treat allergy symptoms, such as itching, hives, runny nose, watery eyes, and sneezing from hay fever (allergic rhinitis) and other allergies, such as allergies to molds and dust mites.
Benadryl is also used to treat insomnia, motion sickness, and mild cases of Parkinsonism.
A main difference between Benadryl and Claritin is that Claritin tends to cause less drowsiness and sedation than Benadryl.

Zyrtec (cetirizine hydrochloride) and Claritin D (loratadine and pseudoephedrine) are antihistamines that treat symptoms such as itching, runny nose, watery eyes, and sneezing from hay fever (allergic rhinitis), allergic skin rashes, and other allergies, such as allergies to molds and dust mites.